Crochet Round Math Checker

Paste a pattern · we do the stitch math · every round PASS or CHECK

Pattern rounds — one per line

Round-by-round audit

Round	Uses	Makes	Declared	Status

Rounds

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Final count

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Stitches worked

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Issues

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How the checker works

Every crochet round is a small equation. Each stitch you work uses a number of stitches from the round below and makes a number of stitches for the round above. When the stitches used equal the previous round’s count, and the stitches made equal the number in brackets at the end of the line, the round is mathematically sound. When they don’t, you have either a typo in the pattern or a round that will pucker, gap or spiral off-shape once you crochet it.

This tool reads standard US notation line by line and reports the math for each round. It understands sc, hdc, dc, tr, inc, dec (also sc2tog and inv dec), sl st, ch and a magic ring start such as 6 sc in MR. Repeats can be written as (sc, inc) x6, (sc, inc) ×6, *sc, inc* 6 times or [2 sc, inc] x6. A trailing number in brackets like (18) is read as the declared stitch count.

Token	Uses	Makes	Notes
`sc` / `hdc` / `dc` / `tr`	1	1	Plain stitch; a leading number multiplies it (`3 sc`).
`inc`	1	2	Two stitches in the same stitch.
`dec` / `sc2tog` / `inv dec`	2	1	Two stitches worked together.
`N sc in MR`	0	N	Magic ring start. `MR 6` also works.
`ch N`	0	N	Chains count as new stitches (foundation or spacing).
`sl st`	1	1	Reported; a final `join` or `sl st to first st` is ignored in the count.
`(…) xN`	×N	×N	Everything inside the group is repeated N times.

Worked example — the classic missing stitch

Suppose a pattern reads R5: (3 sc, inc) x6 (30) and the previous round ended at 24. The group uses 4 stitches and makes 5; repeated six times it uses 24 and makes 30. PASS. Now imagine the designer typed R5: (3 sc, inc) x5, 3 sc (30). The five repeats use 20 and make 25, the three extra single crochets use 3 and make 3 — total used 23, made 28. The checker flags two things: the round only uses 23 of the 24 stitches available, and it makes 28 while the pattern declares 30. That single missing repeat is exactly the error that makes a sphere lean to one side.

The status column tells you which of the two equations failed. “uses X but previous round has Y” means the stitch instructions do not consume the whole round below. “declared X but math gives Y” means the bracket count is wrong or a stitch is missing. A round can fail one, both or neither.

How to fix a round that fails

Check the repeat count first. Ninety percent of errors are a wrong xN. Divide the previous count by the stitches each group uses; the result should be a whole number.
Look for leftover stitches. If the previous count is not divisible by the group, the designer usually adds a few plain stitches before or after the repeat, e.g. sc, inc, (2 sc, inc) x5, sc for a staggered increase.
Re-read the bracket. A declared count that is off by exactly 6 (or 8, or 12) usually means one increase or decrease round was copy-pasted from the wrong place.
Mind the joins. Joined rounds often end with a slip stitch that is not counted; write it as join so the checker ignores it.

FAQ

Does it work with UK terms?

Not yet. Paste US terms only. UK dc equals US sc, UK tr equals US dc; convert first or the stitch heights will be misread, although the counts would still come out the same because plain stitches use and make one stitch each.

What does “uses 30 but previous round has 24” mean?

The instructions on that line consume more stitches than the round below actually has. Either the previous round’s count is wrong, or a repeat number is too high on this one.

Can I paste a whole pattern with notes and headings?

Yes. Lines without any stitch tokens are skipped, and any word the checker does not recognise is listed as a warning below the table instead of stopping the audit.

Why is my declared count blank?

The line has no trailing bracket like (24). The checker still computes the math and carries the computed count into the next round.

Does it check colour changes, stuffing or safety-eye placement?

No. It audits stitch arithmetic only. Those instructions are simply ignored as unknown tokens.

Is anything I paste stored or sent anywhere?

No. Everything runs in your browser; nothing leaves the page.